The present invention relates to cementing operations and, more particularly, to foamed cement compositions, foaming and stabilizing additives, and associated methods.
Foamed cement compositions may be utilized in cementing operations above ground (e.g., in the construction industry), as well as in subterranean cementing operations. Heretofore, foamed cement compositions have included foaming and stabilizing additives which include components such as isopropyl alcohol that may negatively impact aquatic life. In addition, one or more of the components are often flammable, thereby increasing the expense of shipping the foaming and stabilizing additives. Thus, there is a need for foamed hydraulic cement slurries which include foaming and stabilizing additives that may pose less environmental risk and do not include flammable components.
In subterranean cement operations, in primary well cementing, foamed cement compositions may be used to cement off-shore, deep-water wells wherein they may encounter temperatures varying between about 40° F. to about 50° F. The foamed cement compositions may be pumped into the annular spaces between the walls of the well bores and the exterior surfaces of pipe strings disposed therein. The foamed cement compositions are relatively compressible which prevents the inflow of undesirable fluids into the annular spaces. The foamed cement slurries set therein to form annular sheaths of hardened cement. The annular cement sheaths physically support and position the pipe strings in the well bores and bond the exterior surfaces of the pipe strings to the walls of the well bores preventing the undesirable migration of fluids between areas of the formation penetrated by the well bore. Foamed cement compositions also may be used in remedial cementing operations, such as plugging well bores, plugging highly permeable zones or fractures in well bores, plugging cracks and holes in pipe strings, and the like.